The present invention relates to a method and apparatus for providing erasable relief images, and more particularly, to a method and apparatus for providing relief images which may be used in a printing process.
Printing processes, such as flexographic and gravure printing processes, are generally performed by a printing die which is coated with ink for a subsequent transfer to a substrate. For example, the printing die may be in the form of a rotating cylinder wherein the outer surface of the cylinder is formed of a hard material, such as metal, defining a relief image wherein the image is either defined by a raised relief portion, such as is used in flexographic printing, or by a predetermined grouping of cells for retaining ink to be transferred to the work piece, such as in gravure printing. Alternatively, in other applications, the die is in the form of a thick rubber mat that is strapped around a print drum.
In the past, it has generally been necessary to have a specific printing die, or dies, made up to print a particular pattern on a work piece, such that any pattern change requires that a new printing die be made up corresponding to the new pattern. The printing die is typically expensive and time-consuming to produce. Changing the printing die in a machine in order to change the printed pattern is also time consuming, with a resultant down time for the machine incorporating the die.
Accordingly, there is a need for a printing die which facilitates altering of the image printed by the die whereby the time and cost associated with changes in the printed image are reduced.